Measuring weather

Instruments that measure wind direction include weather vanes. These instruments turn in relation to the direction of the wind so "point" to the direction the wind is coming from.

Instruments that measure wind speed are called anemometers. Anemometers generally use rotating devices that spin faster as the wind speed increases. The wind pushes very light cups around a spindle as you can see in the photos.

Wind socks also give a visual indication of wind speed, as the "sock" lengthens out as the wind blows harder, and it sags when the wind is calm.

Wind measurements are important especially at airports, as they aid pilots in knowing which direction to take off and land, and also alert them to strong wind conditions.

ASOS stations use a rotating cup anemometer and wind vane to report wind direction, speed, gusts, and other statistics. In addition to these, other anemometers measure wind speed and direction indirectly, using other sources of information, such as temperature, laser lights, sound waves, pressure tubes, and even ping pong balls! Some of these are especially useful for measuring vertical wind speeds.

Next page   -> in situ, surface observations, wind

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